caliper mounting arrangement

ABSTRACT

A brake caliper assembly includes a caliper body connected to a torque plate via a mating protrusion and cavity that transfer torque through facing abutment surfaces to reduce twisting of the caliper. The mating protrusion and cavity provide a stiff connection and also allow use of a smaller, lighter connecting bolt. This arrangement eases removal and reinstallation of the caliper.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.11/536,252 filed Sep. 28, 2006, which claims priority from U.S.Provisional Application No. 60/752,720 filed Dec. 21, 2005, the contentsof both which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to brake calipers for use with disc brakes. Inparticular, this invention relates to the mounting arrangement of brakecalipers to a vehicle support element.

2. Discussion of Related Art

In typical disc brake assemblies, a rotor is mounted on a wheel hub forrotation. One or more pairs of brake pads, generally designed asfriction material carried on a backing plate, are supported on eitherside of the rotor by a caliper or an anchor bracket. Calipers aredesigned to apply the braking force by moving a piston relative to therotor to thereby move the brake pad into and out of contact with therotor. The pistons are supported in a bore in the caliper and abut thebacking plate of the brake pad to move the brake pad toward the rotorupon application of a braking force. The caliper can be hydraulicallyactuated, for example, to selectively press the brake pads against thesurface of the rotor to stop the rotation of the rotor, and hence thewheel hub, by forcing hydraulic brake fluid into the piston bore.

A fixed type caliper is rigidly mounted to a fixed mounting member ofthe vehicle, such as the frame or axle mount. In such a mount, a torqueplate is bolted to the caliper body and bolted to the fixed mountingmember of the vehicle. The application of braking force to slow or stopthe rotating rotor causes a transfer of torque from the rotor throughthe pads and to the caliper. The force is transferred through thecaliper and torque plate to the mounting member. In this type ofarrangement, the shear force is transferred through the bolts, which cancause the bolts to bend, even when large bolts are used. Bending of abolt causes the caliper to twist, which results in many problems. Atwisted caliper can cause uneven brake pad wear and uneven rotor wear,which can lead to thermal distortion of the rotor, cracking of the rotorand premature failure of the rotor. Twisting of the caliper can alsolead to increased fluid displacement that can cause long pedalphenomenon in which a brake operator experiences a lengthened brakestroke and can also lead to a longer stopping distance. Twisting canalso cause the piston carried by the caliper that actuates movement ofthe brake pads to become lodged in the piston bore.

Additionally, when the caliper needs to be removed and reinstalled, itis difficult to access and manipulate the large bolts needed towithstand the shear forces. This is especially true in cases of mediumand heavy duty vehicles.

There is a need for a caliper and torque plate design that provides fora strong connection that has sufficient stiffness to withstand the shearforce transferred during braking from a rotor through a caliper. Thereis also a need for simplified and easier removal and reinstallation ofthe caliper for service.

SUMMARY OF THE INVENTION

An aspect of the embodiments of the invention relates to providing aconnection between a caliper and torque plate that resists twisting.

An aspect of embodiments of the invention is to provide a caliperassembly with a caliper coupled to a torque plate with a durable, stiffconnection.

A further aspect of embodiments of the invention is to provide a calipermounting arrangement that is easy to access and maneuver to aid inremoval and reinstallation for service.

These and other aspects of the invention can be realized by embodimentsof the invention, which is directed to a brake caliper assembly,comprising a caliper body for supporting a brake pad having a brakingsurface that selectively engages a brake rotor and a torque plateconnected to the caliper body, the torque plate having a mounting memberfor connection to a vehicle support. One of the caliper body and thetorque plate includes a protrusion extending outwardly therefrom and theother of the caliper body and the torque plate includes a cavity that isshaped to correspond to the protrusion and mate therewith so that forcesgenerated during braking are transferred between the caliper body andthe torque plate via the protrusion and cavity.

The protrusion and cavity can be formed in a variety of shapes andconfigurations that provide an abutment surface for the shear forcescreated by the torque during braking to transfer between the torqueplate and the caliper body.

The invention is also directed to a caliper assembly for use with a discbrake system for a vehicle, comprising a caliper body having a bottomsurface and a pair of side walls defining a space therebetween foraccepting a portion of a brake rotor, a torque plate having a topsurface that connects with the bottom surface of the caliper body andhaving a mounting flange for mounting the caliper assembly to a mountingmember, and a fastener fixing the caliper body to the torque plate. Oneof the bottom surface and the top surface has a protruding member andthe other of the bottom surface and the top surface has a correspondingdepressed area that mates with the protruding member to form aconnection between the caliper body and torque plate through whichforces are transferred during braking.

The invention can be further realized in a vehicle brake assembly.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front perspective view of a caliper assembly in accordancewith the invention;

FIG. 2 is a side view of the caliper body of FIG. 1;

FIG. 3 is a side view of the torque plate of FIG. 1;

FIG. 4 is an enlarged side view of a clip positioned in the connectionbetween the caliper body and the torque plate;

FIG. 5 is a top view of the clip of FIG. 4;

FIG. 6 is a side view of the caliper assembly of FIG. 1;

FIG. 7 is a front view of the caliper assembly of FIG. 6;

FIG. 8 is a top view of the torque plate of FIG. 3;

FIG. 9 is a top view of the caliper assembly of FIG. 6;

FIG. 10 is a bottom view of the caliper assembly of FIG. 6;

FIG. 11 is a bottom view of the caliper body of FIG. 2;

FIG. 12 is a side view of the caliper assembly having a protrusion andcavity in the form of a rack;

FIG. 13 is a side view of the caliper assembly having a protrusion andcavity in the form of a boss and indent;

FIG. 14 is a side view of the caliper assembly having a protrusion andcavity in the form of a bushing and groove;

FIG. 15 is a bottom view of a caliper body of a conventional design;

FIG. 16 is a side view of the caliper body of FIG. 15; and,

FIG. 17 is a front view of the caliper body of FIG. 16.

In the drawings, like reference numerals in the various figures denotethe same element.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

This invention is described for use in a vehicular disc brake system.The caliper assembly described below is used for illustrative purposesonly and it will be understood that this invention may be used invarious types of braking systems and with any rotor. The invention canbe used in conventional automobiles, racing vehicles, motorcycles,medium duty vehicles, and heavy duty trucks. As the invention providesan increased ability to withstand high torque applications, it is wellsuited for vehicles having a gross vehicle weight (GVW) of 11,000 poundsor more, such as in trucks, ambulances, and buses. In the descriptionbelow, the brake pads, rotor, and fixed mounting member are not shown asthey are conventionally known.

Referring to FIGS. 15-17, conventional caliper assemblies use a boltedconnection between the caliper body 100 and the torque plate. Thecaliper body 100 includes two opposed side portions 102 and 104 thatextend on either side of a longitudinal axis L. The longitudinal axis Lis generally parallel to the plane of the rotor and perpendicular to theaxis of rotation of the associated vehicle wheel. A space 106 is definedbetween the side portions 102 and 104 in which the brake pads aresupported. The bottom surface 108 of the caliper body 100 is generallyflat. A pair of bolt holes 110 are formed through the caliper body 100in a direction substantially parallel to the rotor and perpendicular tothe axis of rotation that receive large bolts for attaching to a torqueplate. The force transferred from the rotor to the brake pads duringbraking is transferred through the bolts held in bolt holes 110. As thebraking force is entirely transferred through the bolts, it can beappreciated that large bolts must be used. Even with large bolts, theshear force tends to bend the bolts, which twists the caliper body. Theproblems associated with this connection and a twisted caliper,discussed above, lead to numerous performance issues. It is alsodifficult to access and manipulate the bolts during removal andreplacement of the caliper.

In the present invention, seen in FIG. 1, the caliper assembly 10includes a caliper body 12 and torque plate 14 that are held together bybolts, but use a mating protrusion and cavity connection for thetransfer of the shear force from the braking rotor. As explained indetail below, the mating connection allows abutment surfaces on thecaliper body 12 and torque plate 14 to experience the shear force fromthe braking action, instead of the connector bolts, which creates astiffer, more reliable connection between the caliper body 12 and themounting member on the vehicle.

The caliper body 12 includes a pair of opposed side portions 16 and 18that define a space 20 therebetween in which the brake pads are mounted,best seen in FIG. 11. The side portions 16 and 18 have bores 22 thatreceive pistons for actuating the brake pads, as is known. The bottomsurface 24 of the caliper body 12 has a pair of protrusions 26 thatextend downwardly from the end sections of the side portion 16, as seenin FIG. 2. As seen, the protrusions 26 are generally rectangularlyshaped. A pair of bolt holes 28 extends through the protrusion 26, bestseen in FIG. 11.

The torque plate 14 has a mounting flange 30 provided with a series ofopenings 32 to receive bolts for fastening the torque plate 14 to themounting member, as is known. The mounting flange 30 has a surface thatextends generally perpendicular to the axis of rotation of the rotor andgenerally parallel to the longitudinal axis of the caliper body 12. AnABS sensor can be mounted at opening 34. The top surface 36 of thetorque plate 14 is generally flat with a pair of cavities 38 formed atthe end sections. The cavities 38 are formed as generally rectangularchannels, as seen. A bolt hole 40 extends through each cavity 38.

The protrusions 26 are configured to mate with the cavities 38. The boltholes 28 align with the bolt holes 40. A fastener 42, such as a bolt, isinserted through each bolt hole 40 and corresponding bolt hole 28 and issecured with a nut on the caliper body side, for example, to connect thecaliper body 12 to the torque plate 14. Alternatively, the hole can betapped into the torque plate 14 and the fastener threaded into hole 28and hole 40 without a nut. The fasteners 42 connect the caliper body 12to the torque plate 14 so that they do not become disengaged; but, asexplained below, the shear force from the braking action is nottransferred through the fasteners 42, as in conventional constructions.

Each protrusion 26 has an abutment surface 44 on each side. The abutmentsurfaces 44 extend at an angle to the longitudinal axis L, as seen inFIGS. 2 and 11. In other words, the abutment surfaces 44 extend at anangle to the surface of the mounting flange of the torque plate 14. Inthe embodiment shown, the abutment surfaces 44 extend generally at a 90°angle to the longitudinal axis L of the caliper body 12, but theabutment surfaces 44 could also be formed at an acute or obtuse angle tothe longitudinal axis. Each cavity 38 also has an abutment surface 46 oneach side. The abutment surfaces 46 extend at an angle to the face ofthe mounting flange 30, as seen in FIGS. 3 and 8. In the embodimentshown, the abutment surfaces 46 extend generally at a 90° angle to theface of the mounting flange, but the abutment surfaces 46 could also beformed at a different angle that is complementary to the angle of theabutment surfaces 44 of the protrusion 26. The cavity 38 is shaped toextend the width of torque plate 14 and communicate with the rotor space20, as seen in FIG. 9.

Optionally, positioned between the protrusion 26 and the cavity 38 is aclip 50, shown in detail in FIGS. 4 and 5. The clip 50 is generallyU-shaped with an opposed side walls 52 and a base 54. It is sized to fitsnugly within the cavity 38 and extend between the abutment surfaces 44and 46. The clip 50 has a corresponding bolt hole 56 to align with thebolt holes 28 and 40 to receive bolt 42. Typically, the caliper body 12and torque plate 14 are made of ductile iron. The clip 50 is made of amore durable material, such as stainless steel to improve the strengthof the connection and provide corrosion resistant material between themembers.

It is also possible to use a coating or plating rather than the clip 50between the members to offer a corrosion resistant connection. Asuitable coating or plating would be, for example, a zinc-nickel or azinc-iron material. The material could be provided on either orpreferably both adjoining components.

In operation, the brake pads are actuated by the pistons supported bythe caliper body 12 to press against the rotor and impede rotation.Torque from the spinning rotor is transferred to the brake pads andthrough the caliper. Shear force created by the torque is thentransferred from the caliper body 12 to the torque plate 14 via theprotrusions 26 and cavities 38 through the abutment surfaces 44 and 46.It can be appreciated that the connection formed by the abutmentsurfaces 44 and 46 is relatively stiff and not susceptible to bending inthe way merely a bolt would bend under such force as experienced byconventional connections. Since the bolt is no longer used to transferthe shear force, a smaller bolt can be used. So less torque is requiredto tighten the bolt, which eases maintenance. This greatly assists inthe removal and reinstallation of the caliper since smaller bolts areeasier to manipulate and require less force to loosen and tighten.

Of course, the protrusion and cavity can be reversed and function in thesame manner. For example, the protrusion can be formed on the torqueplate and the cavity can be formed in the caliper body. Additionally,while a pair of protrusions and cavities is shown, any arrangement ofprotrusions can be used including one large protrusion or a set of threeprotrusions if desired. Plural protrusions can be aligned or offset toimprove the transfer of force. For example, three triangulatedprotrusions can be provided. The different protrusions and cavities canhave parallel abutment surfaces or abutment surfaces disposed atdifferent angles. Further, the protrusions and associated cavities canbe formed in a different shape than that shown, as long as an abutmentsurface is provided. For example, the mating coupling may berectangular, square, round, oval and angled. Additionally, theprotrusion can be integrally formed with the component or be a separatepiece that fits into a cavity in the component to as to function as aprotrusion.

FIGS. 12-14 show examples of differently shaped couplings. As seen inFIG. 12, a caliper assembly 60 includes a caliper body 62 and torqueplate 64 with a protrusion and mating cavity configured as a pair ofracks 66, 67. Each rack 66, 67 has a plurality of teeth 68, 69 that formpeaks and valleys that interlock with the corresponding peaks andvalleys of the complementary rack.

FIG. 13 shows a caliper assembly 70 including a caliper body 72 andtorque plate 74 with the protrusion and cavity formed as a boss 76 andmating indent 78. The boss 76 and indent 78 can be cylindrical orpolygonal.

FIG. 14 shows a caliper assembly 80 including a caliper body 82 and atorque plate 84 with the protrusion and cavity formed as a separate pinor bushing 85 that fits within a mating groove 86 in the caliper body 82and a mating groove 88 in the torque plate 84. As seen, the bushing 85is polygonal, such as a bar, and can be a shaped as a square orrectangle. It is also possible to shape the bushing 85 as a rod or pinhaving a round or oval shape. In this case, the connection bolt hole canbe adjacent to the protrusion and cavity rather than extending throughit. The coupling can also be made with a stripper bolt.

It will be appreciated by those of ordinary skill in the art that thecoupling can be made in a variety of ways as long as a protrusion andcavity form a mating interlock in order to provide abutting surfaces totake the torque rather than the connecting bolt.

It will be understood that the embodiments disclosed herein areillustrative only and that the invention encompasses modifications andchanges to the particular design features.

1. A brake caliper assembly, comprising: a caliper body for supporting abrake pad having a braking surface that selectively engages a brakerotor; a torque plate connected to the caliper body, the torque platehaving a mounting member for connection to a vehicle support; a fastenerthat fastens the caliper body to the torque plate, and wherein one ofthe caliper body and the torque plate includes at least two protrusionsextending outwardly therefrom and the other of the caliper body and thetorque plate includes at least two cavities that are shaped tocorrespond to the protrusions and mate therewith so that forcesgenerated during braking are transferred between the caliper body andthe torque plate via the protrusion and cavity and said fastener isisolated from shear forces generated by said braking, and wherein eachof said protrusions has two opposing surfaces that are substantiallyparallel to an axis of rotation of said brake rotor and two opposingsurfaces that are substantially orthogonal to said axis of rotation, andeach of said cavities is complementary in shape to its respectiveprotrusion such that each of said opposing surfaces of said protrusionabuts a surface of its respective cavity to isolate said fastener fromsaid shear forces.
 2. The caliper assembly of claim 1, wherein theprotrusions are formed on the caliper body and the cavities are formedin the torque plate.
 3. The caliper assembly of claim 1, wherein theprotrusions are formed on the torque plate and the cavities are formedin the caliper body.
 4. The caliper assembly of claim 1, wherein saidabutting surfaces of said protrusions and cavities are substantiallyplane surfaces.
 5. The caliper assembly of claim 4, wherein theprotrusions and the cavities are polygonal in shape.
 6. The caliperassembly of claim 1, further comprising a clip disposed between theprotrusions and the cavities.
 7. The caliper assembly of claim 6,wherein the clip is made of stainless steel.
 8. The caliper assembly ofclaim 6, wherein the clip is U-shaped.
 9. The caliper assembly of claim1, wherein at least one of the protrusions and the cavities are coatedor plated with corrosion resistant material.
 10. The caliper assembly ofclaim 9, wherein the material is formed on both the protrusions and thecavities.
 11. The caliper assembly of claim 9, wherein the material isformed of zinc-nickel.
 12. The caliper assembly of claim 9, wherein thematerial is formed of zinc-iron.
 13. The caliper assembly of claim 1,wherein a bolt hole extends through the protrusions and the cavities.14. The caliper assembly of claim 1, in combination with a vehicle. 15.The caliper assembly of claim 1, in combination with a vehicle having agross vehicle weight of at least 11,000 pounds.
 16. The caliper assemblyof claim 1, wherein each protrusion is a generally rectangular memberand each cavity is a generally rectangular channel.
 17. The caliperassembly of claim 1, wherein each protrusion is a generally squaremember and each cavity is a generally square channel.
 18. The caliperassembly of claim 1, wherein each protrusion is a boss and each cavityis an indent.
 19. The caliper assembly of claim 18, wherein each bossand indent are generally cylindrical.
 20. The caliper assembly of claim18, wherein each boss and indent are generally elliptical.
 21. Thecaliper assembly of claim 1, wherein each protrusion is integrallyformed with the caliper body.
 22. The caliper assembly of claim 1,wherein each protrusion is integrally formed with the torque plate. 23.The caliper assembly of claim 1, wherein each protrusion is a separatepiece that mates with one of the caliper body and torque plate tofunction as a protrusion.
 24. The caliper assembly of claim 1, whereineach protrusion is a bushing and each cavity is a recess that iscomplementary in shape to said bushing.
 25. The caliper assembly ofclaim 24, wherein each bushing is formed as a bar.
 26. The caliperassembly of claim 24, wherein each bushing is formed as a rod.
 27. Thecaliper assembly of claim 24, wherein each bushing is a separate piecethat is mounted in a corresponding recess formed in the associatedcaliper body or torque plate.
 28. A caliper assembly for use with a discbrake system for a vehicle, comprising: a caliper body having a bottomsurface and a pair of side walls defining a space therebetween foraccepting a portion of a brake rotor; a torque plate having a topsurface that connects with the bottom surface of the caliper body andhaving a mounting flange for mounting the caliper assembly to a fixedmounting member; and, a fastener fixing the caliper body to the torqueplate; means for isolating said fastener from shear forces caused byrelative flexing between the caliper body and torque plate during abraking operation including at least two protruding members extendingfrom one of the bottom surface and the top surface and at least twocorresponding depressed areas located in the other of the bottom surfaceand the top surface that mate with the protruding members to form aconnection between the caliper body and torque plate through which shearforces are transferred during braking, and a corrosion resistant clipdisposed between the protruding members and the depressed areas, whereineach of said protrusions has two opposing surfaces that aresubstantially parallel to an axis of rotation of said brake rotor andtwo opposing surfaces that are substantially orthogonal to said axis ofrotation, and each of said cavities is complementary in shape to itsrespective protrusion such that each of said opposing surfaces of saidprotrusion abuts a surface of its respective cavity to isolate saidfastener from said shear forces.
 29. The caliper assembly of claim 28,wherein at least one of the protruding members and the depressed area iscoated or plated with corrosion resistant material.
 30. The caliperassembly of claim 28, wherein the protruding members and the depressedareas each have abutment surfaces that face each other, wherein theabutment surfaces are oriented at an angle with respect to the mountingflange.
 31. The caliper assembly of claim 28, wherein the protrudingmembers are generally rectangular members and the depressed areas aregenerally rectangular channels.
 32. The caliper assembly of claim 28,wherein the protruding members are generally square members and thedepressed areas are generally square recesses.
 33. The caliper assemblyof claim 28, wherein the protruding members are bosses and the depressedareas are indents.
 34. The caliper assembly of claim 33, wherein thebosses and the indents are generally cylindrical.
 35. The caliperassembly of claim 33, wherein the bosses and the indents are generallypolygonal.
 36. The caliper assembly of claim 28, wherein the protrudingmembers are integrally formed with the caliper body.
 37. The caliperassembly of claim 28, wherein the protruding members are integrallyformed with the torque plate.
 38. The caliper assembly of claim 28,wherein each of the protruding members is a separate piece that mateswith one of the caliper body and torque plate to function as aprotrusion.
 39. The caliper assembly of claim 28, wherein each of theprotruding members is a bushing and each of the depressed areas is arecess that is complementary in shape to said bushing.
 40. The caliperassembly of claim 39, wherein the bushing is formed as a bar.
 41. Thecaliper assembly of claim 39, wherein the bushing is formed a rod. 42.The caliper assembly of claim 39, wherein the bushing a separate piecethat is mounted in a corresponding recess formed in the associatedcaliper body or torque plate.
 43. The caliper assembly of claim 28, incombination with a vehicle.